Proafile Forums

Aluminum Outrigger for Great Barrier Reef

2012-03-12T19:07:55+00:00

Mark Hansen in North Queensland sent in some pics of his new 9.4m (30’-9”) alu outrigger build. Looks pretty amazing!

Hi Guys,

The boat I’ve designed is a bit like one of John Maple’s Constant Camber Tris, but I’ve built it out of marine grade 4mm plate aluminium. After seeing the hull shape, a lot of the locals can’t believe I’ve managed to get an 80ml camber into the side plates, thus bending this very stiff metal two ways.

The interesting thing is, the main hull is virtually finished and still only weighs 378kgs. The reason I went to such a heavy plate is because we live in Far North Queensland, on the Great Barrier Reef, and I have found that plate aluminium endures much more punishment than fibreglass or plywood boats.

Mast is 8.6m high an about 1m tilted back with a 20sm leg of mutton main sail [mylar genoa] 8.0m by 7.75m by 5m all very experimental, and a conventional 10sm jib. The ama and main hull centres will end up about 4m apart. I can’t think of anything more right now so I’ll let you go.

Atlantic vs. Pacific Proas

2012-03-11T04:29:55+00:00

Having your cake and eating it too

If there’s one topic of perpetual interest among proaphiles, it is the debate between “weight to leeward” or “Pacific” proas vs. “weight to windward” or “Atlantic” proas. Is it better to carry most of the weight to windward, or to leeward, or perhaps just keep it more or less centered?

To be clear, we can blame Richard C. Newick for the debate, since it was he who came up with the Atlantic proa in the first place, with his groundbreaking Cheers - the “giant killer” that came in third in the 1968 OSTAR. Unlike all proas until Cheers, Newick placed the ama to lee and the rig to windward, concentrating all the ballast to windward and thus multiplying the righting moment.

As a trimaran designer, Newick no doubt noticed how the windward ama of a tri is always redundant, merely adding weight and windage and not providing any real benefit. With Cheers, he designed a “one ama trimaran”. Genius.

On the other hand, we have ancient Pacific Island culture weighing in on the Pacific side, the long and slender canoe hull, elegantly counterpoised by the ballast ama to windward. While the approach is somewhat counter-intuitive to Western ideas about sailboat design, it is true that up until WWII and the invention of marine plywood, the fastest sailboats in the world were traditional Pacific sailing canoes. It was Woody Brown who brought the two together in Manu Kai, the first modern catamaran. Russell Brown (no relation to Woody) is the most well-known and successful advocate of the modern Pacific type.

It occurs to me that with a proa, it’s not actually necessary to choose between one or the other. What if we designed a proa to sail equally well in Atlantic or Pacific mode, and if we did, would there be any advantages? Imagine a proa that was designed to sail in light weather as a Pacific proa, but in heavy weather as an Atlantic proa. Apparently, I’m a bit late on this, see Malcolm Smith’s Mi6:

The outrigger is the same length as the main hull for speed and also to provide maximum diagonal stability in Atlantic mode. The construction technique is identical to that of the main hull and also incorporates a rounded chine plank.

The outrigger has enough volume to carry twice the displacement of the boat. It is however much narrower than the main hull and has less rocker or spring in the keel line. The difference in hull shapes is intended to make the boat as efficient as possible through it’s entire speed range. In light winds it would be sailed in Pacific mode, flying the outrigger as much as possible to reduce wetted surface. The main hull with much of it’s volume concentrated around midships has a lower prismatic coefficient, Cp, providing lower resistance at lower speeds. The outrigger conversely has been designed with a high Cp. The ends are relatively more voluminous than the main hull, giving lower resistance at higher speeds. Therefore, in heavier winds, the proa would be sailed in Atlantic mode, with the outrigger becoming the major load bearing hull, possibly even to the point where the main hull is “flown”.

It should be noted that the above idea is not unique to proas. Trimarans work in much the same way without even thinking about it but pay a price in terms of weight, windage and cost of the extra hull. Conventional catamarans do not have the advantage of the ability to select the right hull for the right conditions, and with two identically shaped hulls better suited to higher speeds, are not often noted for their light air performance.

Bingo. A yacht suitable for both light and strong air, just choose the side that suits you!

Jzerro sailing video

2012-01-16T00:17:38+00:00

Hello proa enthusiasts. We put together a video from clips taken this fall on a cruise to Canada.
http://www.youtube.com/user/ptwatercraft
We did not have a waterproof camera. Too bad, because we had LOTS of wind and heavy rain at times. This would have made for exiting video if we had had a waterproof camera.
In any case, we thrashed the #### out of the old girl on the way home and she seemed to love it. Lots of upwind in 30 knots or more of wind. The short clip of the boat sailing under reefed main only was taken in 35 to 40 knots and heavy rain.
The single outrigger motorboat is a boat I designed for my buddy Josh. It’s his family car and pickup truck. It’s powered by a 20 hp outboard and goes about 18 knots. He put 7200 miles on this boat in less than two years and sometimes carries huge stacks of plywood and other heavy things with it.
I hope you like the video,
Russell

25’ Rowboat With Proatential

2012-01-08T03:28:00+00:00

I found this cool 25’ Cruising Row Boat on Craigslist in Nordland (near Port Townsend, WA).

This beautiful cruising row boat was designed & built by Heath Snows in 1992 on Marrowstone Is. She has been rowed over 3,000 miles (a round trip from Port Townsend to Glacier Bay plus another shorter trip). This is not a daily knock-about boat. She can carry 6 months supplies & has a 30 gallon (approx) bilge water tank. It doesn’t have a sail. The hull is in very good condition but the exterior needs new fiberglass, the old glass has been removed, the hull & deck sanded clean & smooth & fully coated with epoxy. The floors need replacing & reconfiguring to your personal needs. The hull is fully symmetrical, i.e. all four quarters are identical.

Specs:
LOA; 25’ / LWL; 25’ / Draft; 6”+ / Beam @ water line; 3’ 6” / Beam @ deck; 4’ 6” / Hull depth; 18”
Hull: 5/16” Western Red Cedar bead & cove strip planked
Deck: 1/4” Western Red Cedar bead & cove strip planked
Piantedosi RowWing drop-in rowing system w / 2 pairs carbonfiber oars.
There is also a sunbrella tent that fits over the cockpit (not for use while rowing)

Other possibilities;
It would make an excellent proa or trimaran and it could be a great base for an all electric solar & battery system. If you are interested in the hull only I will negotiate on the price.

Note: “the hull is fully symmetrical”. This baby is just begging to be turned into a cool little adventure cruising proa! The imagination runs wild. I’m picturing a hybrid rowing/sailing craft - “Sail when you can, paddle when you must” would be the mantra.

What would YOU do with such excellent raw material?

Palindrox

2011-12-24T04:53:56+00:00

Here’s another musing on the 24’ proa accommodation conundrum.

Dinghy on a stick took the approach of being an outdoor boat. Its a daysailer with a big open cockpit,with your feet in the vaka. And it happens to use a pram as a safety ama.

Palindrox goes the other way. Its all accommodation. You sit inside all the time. There’s no cockpit, just a comfy little cabin to drive from. One of my favorite designs like that is Matt Layden’s Paradox ...

http://www.microcruising.com/paradox1.htm

and then there’s the standing headroom of Phil Bolger’s birdwatcher…

http://bolgerbirdwatcher.blogspot.com/

and of course Blondie Hasler’s Jester is one of the earliest of the type…

http://www.jesterinfo.org/jester.html

and our own editor’s Samwise series always intrigued me….

http://proafile.com/search/results/3521adfc46eec0d3be8a8a2429cb50e2/

So Palindrox is a Paradox that’s a Palindrome. It has an open airy greenhouse that provides a lot of protection from the elements while at the helm. Its 56” from the peak of the cabin top to the chine. And the green house is 44 inches wide at the base. Each of the two helm stations would have comfy sling chairs to sit in. Generous hatches (not shown) would open her up in nice weather. Cruising accommodations would be a single bunk, 80” long. Two people could ride comfortably in the greenhouse, facing each other for socializing, sitting in tandem underway.. That’s all that should go anyway. Joyriding would take place on a simple bench to windward, also not shown yet.

I’ve rigged it as a cambered junk measuring 211 sq ft. Maybe when you’re racing you’d raise a headsail too.

Anyway, this boat has a LOT more windage and skin than the dinghy on a stick. It will take longer to make (I think…) than the dinghy on a stick. But it might just work. I’ll add some more detail to the model soon. including hatches, stays, etc.

All the best,
Chris

Call For Writers on Proas

2011-12-16T03:54:40+00:00

Ed Maurer, publisher of Canoe Sailing Magazine, has sent me a note announcing that CSM is expanding it’s horizons to include small multihulls, including sailing outriggers and proas. Not that they were ever discriminatory in the least, certainly not the New York Yacht Club, but something about the name “canoe sailing” conjures up images of sailing in your derby. Well, that’s about to change, since the new name of CSM is Skinny Hull Canoe & Kayak Sailing Magazine. Consider yourselves included.

I think this is great. We all know the only thing wrong with an American canoe is it’s lack of an appendage*. Go give Skinny Hull some love, and if you happen to have some outrigger or proa related writing on the back of your hard drive, dust it off and send it in.

*Ama

Dinghy on a stick v.2

2011-12-08T17:13:19+00:00

Here are some more recent musings on the dinghy as lee pod concept. With a less *aesthetically challenged* pod, it looks a lot better.

From a looks perspective, having the pod level looks great. But I wonder if canting it, so that the bottom hits the water more or less flat upon immersion, might have better dynamic characteristics.

Anyway, this is an all new, more carefully constructed model—this one is fully parametric. It doesn’t explode as much as the green one did. But still 24’ LOA, 12’ center to center beam.

The more I think about it, the more having a little dinghy makes sense for the Bay Area. It makes it possible to leave it anchored out, rather than being tied to a marina. I have a novel outboard idea brewing as well.

Best,
Chris

Less is More

2011-12-03T11:21:53+00:00

I am not sure how a post like this may lead to responses, but I thought I’d go ahead anyway.

While indirectly technical, this essay is a philosophical. Yet I can’t imagine a better audience for these kinds of thoughts on proas than those who read and write here.

***

I am writing by candle light and the battery in my laptop, for the power has been out all day. This has a peculiar bearing on the topic at hand because I had been pondering the power of limits, and then suddenly, the universe provided me with a perfect example.

Let me explain what I mean by “The Power of Limits.” I think I first observed this in art work. First, I figured out that my paintings were flawed because my drawing skills were out of balance with my colorist skills, so I decided to take a break from painting and draw more.

Then, I discovered that I could take everything I needed to produce nice work on a backpacking trips. The amount of material I needed went from a bulky twenty pound package to a slim, few ounce satchel. A world of possibilities opened. Suddenly, I could do finished, original art on a mountaintop.

Rather than be frustrated by a limitation, I embraced it. The result, for me, was better art; moreover, art that could not have been done at all any other way.

Working as a carpenter, it was always nice to not have to haul around a lot of junk. In home construction, I would always see these guys who thought they were so cool with all their crap. Why then was it taking them a week to do a day’s work? My answer—and it is an answer shared by many high production workers—is that you have to understand what your margin of error is. Cabinet work requires high accuracy in the finish, but rough framing does not. If you know how to play that limit, your production can increase exponentially.

These days, when I’m not doing schoolwork (I’m one of those old guys who went back to school), I carve wood. At first, I used only hand tools, but I soon discovered I wasn’t going get much accomplished that way, so I took up the chain saw. This may seem contrary to my thesis, but the fact is I discovered that a surprising degree of delicacy can be had with a chain saw; furthermore, by letting the wood lay rough and not fussily primping and polishing, the work took on a vibrant immediacy. Best, I could finish a piece in a matter of hours and minutes instead of days and weeks.

Now, as I embark on a proa building project, I learn to embrace the limits of these boats. These are not “flaws.” They don’t need to be “fixed.” Proas have limited sail carrying capacity and limited accommodation. This is just in the nature of what they are. I know there are many people much more clever than me who have pushed those limits, and perhaps there are some who might claim to have transcended them, but I do not want to walk that path.

For me, The Way of the Proa is the way of a boat who dreams of being a bird.

Now, I am thinking of that big bag of North windboard sails that my brother left in the garage. He said I could have them. (Really rather high end gear.) Maybe I should be building a boat to match the sail rather than the other way round?

Ooooh… chills

Limits. You see? You get things DONE. You don’t have to HAVE in order to DO. I just saved a BUNCH of time and money. Thank you, power failure.

Be well,
Rick

HIGH SPEED SAILING. pure adrenaline!

2011-12-03T08:53:40+00:00

Hi Guys!

If anybody is interested in high speed sailing, laminating technology, last hour news and in general remarks PERFORMANCE AND OUTSTANDING SAILING NEWS AND UPDATES, I would suggest looking and subscribing to the French magazine VOILES ET VOILIERS.
The web subscription allows you to receive, news data and info of the market and technology as well as offers, parts information etc.

I was just following the giant trimaran BANQUE POPULAIRE intent of record braking world tour presently held by GRUPAMA,(is 900 Ml. ahead) and there is a log photo that shows speeds of 42,06 Kn!!!!

cheers

The Flying Apple Crate

2011-12-02T00:50:58+00:00

Hi Proa-types,

I really want one of John Harris’ Madness style proas. First of all, its gorgeous, and beauty counts in a boat. I love that he took the principles of Russell Brown’s boats and created a stitch and glue kayak kit out of them. Did I mention its gorgeous?

But as I enter year 2 of my 16” Wa’apa build, I’m confident that I do not have the time to complete such a project without it seriously interfering with my family life, financial situation or both. And having it built is expensive. Very expensive.

So while I’m figuring out where I’m going to scrape together the money to have one built for me, I started doodling a minimum proa for sailing on San Francisco Bay. Coincidentally, the size I came up with is about the depth of my garage—24 feet. At that length, I trade in accommodation for a cozy, high sided cockpit that is self draining in the main hull. Maybe you could cover it and roll out some air mattresses, but this is a daysailer!

The plywood main hull is single chined. In profile, the topsides of the hull rise up to form a hump in the middle of the boat, to hang the lee pod off of, in the classic Newick/Brown style. In early drawings I had a pod shaped bit on the windward side too, but it seemed like a lot of work to build a cockpit inside the pod. So to save weight and time, I left the windward pod out. So the single sided cockpit just hangs off the windward side, like an apple crate. Outboard of that is a beam to spread mast compression loads out to the akas.

The akas are plywood box beams that taper fit into sockets in the vaka and ama. Then I’d have a couple bolts or lashings to keep them seated in their tapers.

The ama is based on Harmen Hielkema’s, described in this reposting of Russell’s Proa File International posting.

http://www.wingo.com/proa/brown/observations_on_pacific_proas.html

...that’s a good enough recommendation for me.

The rudders would also be Russ Brown/Newick inspired—with the clever foam crash box and easier to fabricate rectangular cases.

I’ve drawn it with a James Brett inspired cambered junk rig (even thought it looks flat in the rendering). That would be an amazing rig if it works up wind. James says it does! I sized it at about 250 sq feet on a 24’ mast. I could add a jib for light air.

But what I’d really like to try is the twist control gaff rig that Paul Bieker developed for the PT 15 dinghy. There is a great article about this in Wooden Boat #193. The gaff rotates with the mast to control twist! Plus, the bendy top of the sail goes down when you reef, so the top of the sail acts the same whether you are reefed or not. Super cool. I’d pair that with hanked on jibs and the jib catching nets used on Pacific Bee.

Anyway, when I get a minute I’m going to work on further Dierking-izing the design; take more away and focus on increased simplicity.

Let me know if you have any thoughts.

All the best,
Chris